Periodic Table of Elements
Click or tap any element for its name and atomic weight, plus the electron configuration for elements 1–92. Search by number, symbol or name, practice with hidden names, or print a blank periodic table.
Use the arrow keys to move between cells, Enter for details and Esc to close.
Select any element to see its name, atomic weight and electron configuration.
- Atomic weight (mass)
- Position
- Category
- Electron configuration
Molecular weight calculator Full electron configuration
Periodic Table of Elements
Alkali metals Alkaline earth metals Transition metals Lanthanides Actinides Other metals Metalloids Other nonmetals Halogens Noble gases Properties not established
How to read the periodic table
The small number in each cell is the atomic number, the count of protons in the nucleus. The large letters are the element symbol, and the name sits below. Turn on Atomic weights to add a fourth line.
Columns are groups, numbered 1–18 from left to right. Rows are periods, numbered 1–7 from top to bottom. Elements in the same group tend to behave alike chemically.
The lanthanides (57–71) and actinides (89–103) sit in two rows under the table so it does not get too wide. In the main grid, markers labeled 57–71 and 89–103 stand in the group 3 slot of periods 6 and 7.
Metals, metalloids and nonmetals
The colors follow a common teaching convention, not an official IUPAC classification. This table counts boron, silicon, germanium, arsenic, antimony and tellurium as metalloids. Astatine is marked “Metal, metalloid or nonmetal: sources differ.” Elements 104–118 are marked “properties not experimentally established,” though they keep their group names by position.
Groups 3–12 are shown as transition metals (elements 104–112 only by position); some sources leave group 12 (zinc, cadmium, mercury) out. Every category also has a marker (● ○ ■ ▲ and so on) and a text label, so it never relies on color alone.
What atomic weight (atomic mass) and ± mean
An atomic weight is the average relative mass of an element’s natural isotopes, so strictly it has no unit of its own. Textbooks usually call the same number the atomic mass and write it in amu. Class tables often round it (iron 55.85), so use the table your class gives you. The ± part is the uncertainty; it covers both measurement limits and natural differences between samples.
Values come from the IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW), abridged table 2024. That is why argon shows 39.95 ± 0.16 instead of the older 39.948, and zirconium shows 91.222 after the 2024 revision (it was 91.224).
For 14 elements, including hydrogen, carbon and oxygen, natural atomic weights span a range, and the value shown is IUPAC’s conventional one. Thirty-four elements have no standard atomic weight: technetium (43), promethium (61), elements 84–89 and everything from 93 on. They have no stable isotopes, so this page does not add a mass number of its own.
Aluminum or aluminium?
Both are correct. US schools use aluminum and cesium; IUPAC uses aluminium and caesium. This page shows the US spelling and notes the IUPAC one in the details, and search accepts either (sulphur works too).
Practice and a printable periodic table
Choose Practice, then Hide names or Hide symbols and a range (1–20, 1–36 or all 118). Hidden cells show a “?” and keep their atomic number; tap one to reveal it. Reveal all shows the answers, and Reset hides them again. Nothing is scored or saved.
Print / Save PDF prints one landscape page: the full labeled table, or a blank periodic table with numbers only or numbers and symbols. In grayscale the category markers still tell the groups apart. Pick “Save as PDF” in the print dialog to keep a file.
About the data
Data checked September 30, 2026. The table loads with the page, so searching and practice run in your browser and nothing you look up is sent anywhere.
Frequently asked questions
How many elements are on the periodic table?
There are 118 named elements, from hydrogen (1) to oganesson (118). Elements 113, 115, 117 and 118 were verified at the end of 2015, completing period 7, and named in 2016.
Why doesn’t technetium have an atomic weight?
All of technetium’s isotopes are radioactive, and it has no fixed natural isotopic composition, so IUPAC gives it no standard atomic weight. Some class tables print a bracketed mass number instead; that is not an atomic weight.
Aluminum or aluminium?
Aluminum is the US spelling and aluminium is the IUPAC spelling. The page shows Aluminum and Cesium, notes the IUPAC spellings in the details, and search finds the element either way.
Why is argon 39.95 and not 39.948?
CIAAW gives argon’s atomic weight as a range because natural argon varies. Its abridged value is 39.95 ± 0.16, which replaced the older single value of 39.948.
Is atomic weight the same as atomic mass?
In school, yes: most textbooks call this number the atomic mass and write it in amu. Strictly, atomic weight is a ratio with no unit, and one atom’s own mass (in u) differs from isotope to isotope.
Can I print a blank periodic table?
Yes. Open Print / Save PDF, choose Blank (numbers only) or Blank (numbers and symbols), and then Open print dialog.
Does the whole table fit on a phone?
Yes. All 18 groups fit across a phone screen held upright, with the atomic number and symbol in each cell. Tapping a cell opens the details from the bottom, and the List view gives one element per row.